1. Field of the Invention
The present invention relates to light emitting diode devices, and more specifically to a light emitting diode device for outdoor luminaires.
2. Description of Related Art
Light emitting diodes (LEDs) are commonly used as light sources in illuminating devices such as traffic lights, street lamps, billboards, displays and so on. The LED has several advantages such as high brightness, long lifespan and low-power consumption over incandescent and fluorescent lamps.
Conventional illuminating devices incorporating LEDs generally generate diffusion-type light field. The diffusion-type light field is substantially circular. In other words, a part of the light field along an x-direction is substantially the same as a part of the light field along a y-direction. However, this type of light field of the LED illuminating device is not always required in our daily life, such as in a street lamp, which has a strip-type light field requirement. If the diffusion-type light field is applied in the street lamp, part of light will not be used, which decreases utilization rate of the light emitted from the LEDs.
For the foregoing reasons, it is desirable to provide a LED illuminating device which can overcome the described limitations.